U.S. patent number 8,287,414 [Application Number 12/679,512] was granted by the patent office on 2012-10-16 for transmission device having a variator.
This patent grant is currently assigned to ZF Friedrichshafen AG. Invention is credited to Gerhard Bailly, Walter Fischer, Jurgen Pohlenz, Thomas Ratzmann, Tobias Weber.
United States Patent |
8,287,414 |
Weber , et al. |
October 16, 2012 |
Transmission device having a variator
Abstract
A continuously variable transmission device comprising a
variator and a secondary power splitting. For power splitting, a
planetary gear set has a first shaft coupled to the transmission
input, a second shaft of the gear set coupled a first shaft of the
variator, and a third shaft of the gear set couples a second shaft
of the variator. First and second shift elements are provided to
switch between first and second gear ratio ranges. Via the
variator, the gear ratio is continuously variable within the gear
ratio range and the two gear ratio ranges overlap. To implement the
first gear ratio range, the second shaft of the gear set is
connected, via the first shift element, to the transmission output,
and to implement the second gear ratio range, the third shaft of
the planetary gear set is connected, via the second shift element,
to the transmission output.
Inventors: |
Weber; Tobias (Radolfzell,
DE), Bailly; Gerhard (Friedrichshafen, DE),
Ratzmann; Thomas (Meckenbeuren, DE), Fischer;
Walter (Friedrichshafen, DE), Pohlenz; Jurgen
(Ravensburg, DE) |
Assignee: |
ZF Friedrichshafen AG
(Friedrichshafen, DE)
|
Family
ID: |
40225346 |
Appl.
No.: |
12/679,512 |
Filed: |
August 15, 2008 |
PCT
Filed: |
August 15, 2008 |
PCT No.: |
PCT/EP2008/060757 |
371(c)(1),(2),(4) Date: |
March 23, 2010 |
PCT
Pub. No.: |
WO2009/047035 |
PCT
Pub. Date: |
April 16, 2009 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20100197439 A1 |
Aug 5, 2010 |
|
Foreign Application Priority Data
|
|
|
|
|
Oct 2, 2007 [DE] |
|
|
10 2007 047 194 |
Jul 16, 2008 [DE] |
|
|
10 2008 040 441 |
|
Current U.S.
Class: |
475/72; 475/302;
475/210 |
Current CPC
Class: |
F16H
47/04 (20130101); F16H 37/084 (20130101); F16H
2200/0039 (20130101); F16H 2200/2005 (20130101); F16H
37/0813 (20130101); F16H 3/728 (20130101); F16H
2037/0873 (20130101) |
Current International
Class: |
F16H
37/08 (20060101); F16H 47/04 (20060101) |
Field of
Search: |
;475/207,208,216,218,83,81,72,210,211,302
;74/730.1,731.1,732.1,733.1 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
197 650 |
|
Oct 1957 |
|
AT |
|
1 069 978 |
|
Nov 1959 |
|
DE |
|
976 055 |
|
Jan 1963 |
|
DE |
|
1 174 126 |
|
Jul 1964 |
|
DE |
|
1 952 966 |
|
Apr 1970 |
|
DE |
|
27 57 399 |
|
Sep 1978 |
|
DE |
|
28 54 375 |
|
Jun 1980 |
|
DE |
|
29 04 572 |
|
Aug 1980 |
|
DE |
|
28 44 116 |
|
Jul 1982 |
|
DE |
|
80 18 579 |
|
Jun 1984 |
|
DE |
|
36 22 045 |
|
Mar 1987 |
|
DE |
|
42 06 023 |
|
Sep 1993 |
|
DE |
|
37 86 996 |
|
Dec 1993 |
|
DE |
|
94 02 493 |
|
Jul 1995 |
|
DE |
|
44 43 267 |
|
Jun 1996 |
|
DE |
|
197 51 993 |
|
May 1998 |
|
DE |
|
198 43 069 |
|
May 1999 |
|
DE |
|
100 03 174 |
|
Sep 2000 |
|
DE |
|
199 54 894 |
|
Dec 2000 |
|
DE |
|
100 47 398 |
|
Apr 2002 |
|
DE |
|
202 08 495 |
|
Jan 2003 |
|
DE |
|
601 03 717 |
|
Oct 2004 |
|
DE |
|
103 19 252 |
|
Nov 2004 |
|
DE |
|
10 2006 004 223 |
|
Aug 2006 |
|
DE |
|
10 2006 025 347 |
|
Dec 2007 |
|
DE |
|
10 2006 025 348 |
|
Dec 2007 |
|
DE |
|
11 2004 000 874 |
|
Apr 2008 |
|
DE |
|
10 2007 049 412 |
|
May 2008 |
|
DE |
|
0 234 135 |
|
Sep 1987 |
|
EP |
|
0 234 136 |
|
Sep 1987 |
|
EP |
|
0 235 466 |
|
Sep 1987 |
|
EP |
|
0 465 752 |
|
Jan 1992 |
|
EP |
|
0 577 282 |
|
Jan 1994 |
|
EP |
|
0 683 875 |
|
Apr 1998 |
|
EP |
|
1 541 898 |
|
Jun 2005 |
|
EP |
|
1 855 029 |
|
Nov 2007 |
|
EP |
|
1 930 627 |
|
Jun 2008 |
|
EP |
|
1197 751 |
|
Jan 1958 |
|
FR |
|
1 483 053 |
|
May 1966 |
|
FR |
|
1 206 196 |
|
Sep 1970 |
|
GB |
|
2007-85517 |
|
Apr 2007 |
|
JP |
|
86/00963 |
|
Feb 1986 |
|
WO |
|
99/15813 |
|
Apr 1999 |
|
WO |
|
00/43695 |
|
Jul 2000 |
|
WO |
|
2004/038257 |
|
May 2004 |
|
WO |
|
2004/072512 |
|
Aug 2004 |
|
WO |
|
2006/042434 |
|
Apr 2006 |
|
WO |
|
2007/014706 |
|
Feb 2007 |
|
WO |
|
2008/004360 |
|
Jan 2008 |
|
WO |
|
Primary Examiner: Holmes; Justin
Assistant Examiner: Nguyen; Lillian
Attorney, Agent or Firm: Davis & Bujold, P.L.L.C.
Claims
The invention claimed is:
1. A transmission device (3) having at least one variator (5) for
the continuous variation of a gear ratio and having secondary power
splitting; a planetary gear set (8) being provided for power
splitting; a first shaft (9) of the planetary gear set (8) being
coupled to a transmission input (6); a second shaft (10) of the
planetary gear set (8) being coupled to a first shaft (12) of the
variator (5); a third shaft (11) of the planetary gear set (8)
being coupled to a second shaft (13) of the variator (5); at least
one of a first shift element (14) and a second shift element (15)
being provided for switching between a first gear ratio range and a
second gear ratio range, within which the gear ratio is
continuously varied by the variator (5), and the first and the
second gear ratio ranges at least partially overlap one another;
the second shaft (10) of the planetary gear set (8) being
connected, via the first shift element (14), to a transmission
output (7) in order to implement the first gear ratio range; the
third shaft (11) of the planetary gear set (8) being directly
connected to the second shift element (15), and being connectable,
via the second shift element (15), to the transmission output (7)
in order to implement the second gear ratio range; at least one
idler gear (16) being rigidly connectable, via one of the first and
the second shift elements (14, 15), to one of the second shaft (13)
of the variator (5) and the third shaft (11) of the planetary gear
set (8); and the second shaft (10) of the planetary gear set (8)
being one of directly connected to the first shift element (14),
and directly coupled to at least one idler gear (29, 31).
2. The transmission device according to claim 1, wherein a
countershaft (17), arranged in parallel to the second shaft (13) of
the variator, is operatively connected to the transmission output
(7).
3. The transmission device according to claim 1, wherein at least
one idler gear (16) is operatively connected to a gear wheel (18)
supported by the countershaft (17).
4. The transmission device according to claim 1, wherein the first
and the second shift elements (14, 15) are arranged on at least one
of the third shaft (11) of the planetary gear set (8) and the
second shaft (13) of the variator (5).
5. The transmission device according to claim 1, wherein the second
shaft (10) of the planetary gear set (8) is operatively connected,
via a transmission unit, to the first shaft (12) of the variator
(5).
6. The transmission device according to claim 1, wherein the
variator (5) is a hydrostatic device which comprises at least one
pump and at least one motor operatively connected thereto, via a
hydraulic circuit, and both the at least one pump and the at least
one motor are adjustable.
7. The transmission device according to claim 1, wherein the first
shaft (9) of the planetary gear set (8) forms planet carrier, the
second shaft (10) of the planetary gear set (8) forms a ring gear,
and the third shaft (11) of the planetary gear set (8) forms a sun
gear.
8. The transmission device according to claim 7, wherein the
variator (5) is a hydrostatic device and a pump of the variator (5)
is connected, via the first shaft (12) of the variator (5), to the
ring gear (10) of the planetary gear set (8) and, in order to
implement a rotational speed equal to zero in a region of the
transmission output (7), a power flow of the variator (5) is locked
and the second shaft (13) of the variator (5) is freely rotated
without power transmission.
9. The transmission device according to claim 1, wherein a reverse
direction of rotation, between the transmission input (6) and the
transmission output (7), is implemented by a valve device of a
hydraulic circuit of the variator (5) by which a pumping direction
in the hydraulic circuit is reversed.
10. The transmission device according to claim 1, wherein a
plurality of gear wheel pairs (20 to 20n) are located between the
third shaft (11) of the planetary gear set (8) and the transmission
output (7) which are connectable, via additional shift elements (21
to 21n), to implement additional gear ratio ranges.
11. The transmission device according to claim 10, wherein at least
one of the gear wheel pairs comprises an intermediate gear (24) for
implementing a reverse direction of rotation between the
transmission input (6) and the transmission output (7).
12. The transmission device according to claim 1, wherein a third
shift element (28) couples the second shaft (10) of the planetary
gear set (8) to the transmission output (7) for implementing a
third gear ratio range which overlaps with the second gear ratio
range.
13. The transmission device according to claim 1, wherein the first
shift and the second shift elements (14, 15, 21 to 21n, 22, 28) are
each frictionally engaged power shift elements.
14. The transmission device according to claim 1, wherein the
variator (5) is a hydrostatic device which comprises at least one
pump and at least one motor operatively connected thereto, via a
hydraulic circuit, and both the at least one pump and the at least
one motor are bent axis devices.
15. The transmission device according to claim 1, wherein the
second shaft (10) of the planetary gear set (8) is directly
connected to the first shift element (14).
16. The transmission device according to claim 1, wherein the
second shaft (10) of the planetary gear set (8) is directly
connected to at least one idler gear (29, 31).
17. The transmission device according to claim 1, wherein at least
one idler gear (29, 31) is both directly connected to at least one
shift element (14, 28) and is directly coupled to the second shaft
(10).
18. The transmission device according to claim 1, wherein at least
two idler gears (29, 31) are both directly connected to respective
shift elements (14, 28) and directly coupled to the second shaft
(10).
19. A transmission device (3) having at least one variator (5) for
the continuous variation of a gear ratio and having secondary power
splitting; a planetary gear set (8) being provided for power
splitting; a first shaft (9) of the planetary gear set (8) being
coupled to a transmission input (6); a second shaft (10) of the
planetary gear set (8) being coupled to a first shaft (12) of the
variator (5); a third shaft (11) of the planetary gear set (8)
being directly connected to a second shaft (13) of the variator
(5); at least one of a first shift element (14) and a second shift
element (15) being provided for switching between a first gear
ratio range and a second gear ratio range, within which the gear
ratio is continuously varied by the variator (5), and the first and
the second gear ratio ranges at least partially overlap one
another; the second shaft (10) of the planetary gear set (8) being
connected, via the first shift element (14), to a transmission
output (7) in order to implement the first gear ratio range; both
the third shaft (11) of the planetary gear set (8) and the second
shaft of the variator (5) being directly connected to the second
shift element (15) and being connectable, during engagement of the
second shift element (15), to the transmission output (7) for
implementing the second gear ratio range; and at least one idler
gear (16) being rigidly connectable, via one of the first and the
second shift elements (14, 15), to one of the second shaft (13) of
the variator (5) and the third shaft (11) of the planetary gear set
(8).
20. A transmission device (3) having at least one variator (5) for
the continuous variation of a gear ratio and having secondary power
splitting; a planetary gear set (8) being provided for power
splitting; a first shaft (9) of the planetary gear set (8) being
coupled to a transmission input (6); a second shaft (10) of the
planetary gear set (8) being coupled to a first shaft (12) of the
variator (5); a third shaft (11) of the planetary gear set (8)
directly connecting a sun gear of the planetary gear set (8) with
to a second shaft (13) of the variator (5); at least one of a first
shift element (14) and a second shift element (15) being provided
for switching between a first gear ratio range and a second gear
ratio range, within which the gear ratio is continuously varied by
the variator (5), and the first and the second gear ratio ranges at
least partially overlap one another; the second shaft (10) of the
planetary gear set (8) being connected, via the first shift element
(14), to a transmission output (7) in order to implement the first
gear ratio range; both the third shaft (11) of the planetary gear
set (8) and the second shaft of the variator (5) being directly
connected to the second shift element (15) and being connectable,
during engagement of the second shift element (15), to the
transmission output (7) for implementing the second gear ratio
range; and at least one idler gear (16) being rigidly connectable,
via one of the first and the second shift elements (14, 15), to one
of the second shaft (13) of the variator (5) and the third shaft
(11) of the planetary gear set (8).
Description
This application is a National Stage completion of
PCT/EP2008/060757 filed Aug. 15, 2008, which claims priority from
German patent application serial no. 10 2007 047 194.9 filed Oct.
2, 2007 and German patent application serial no. 10 2008 040 444.1
filed Jul. 16, 2008.
FIELD OF THE INVENTION
The invention relates to a transmission device having at least one
variator for the continuous variation of transmission and having
secondary power splitting.
BACKGROUND OF THE INVENTION
From DE 10 2006 025 348 A1 a power-split transmission having a
variator designed as hydrostatic device is known. The power-split
transmission is equipped with a power splitting planetary gear set,
wherein a shaft of the planetary gear set is operatively connected
to a first shaft of the variator, and in this manner an adjustable
pump can be driven. An additional shaft of the planetary gear set
is connected via a gear wheel to a second shaft of the variator,
which, in turn, is operatively connected to a hydraulic motor of
the variator. The third shaft of the planetary gear set is
connected to a transmission input of the power-split transmission
which is connected to a drive device.
In addition, the second shaft of the variator is designed with a
plurality of fixed gears which mesh with a plurality of idler gears
arranged on a countershaft, wherein the idler gears can be
connected rigidly to the countershaft via shift elements to
implement different driving modes and/or transmission ratios for
forward driving and at least one driving mode for reverse
driving.
Disadvantageously, the alternation between the driving modes cannot
be carried out in a synchronous manner, so that to avoid an
interruption in torque flow, in any case during a change in driving
mode, power shifting with simultaneous correction of transmission
ratio must be carried out in the region of the hydrostatic device.
During such shifts, under certain circumstances disturbing reactive
torques in the drive train of a work machine occur, which
negatively impact a sequence of operation of a work machine
equipped with the above-described power-split transmission and are
perceived by an operator as a jerk in the working machine.
SUMMARY OF THE INVENTION
Therefore the problem of the present invention is to provide a
transmission device by which, in critical operating states of a
work machine, synchronous shifts in driving modes can be carried
out and which has a simple design.
The transmission device according to the invention is designed with
at least one variator for the continuous variation of transmission
and with secondary power splitting, wherein a planetary gear set is
provided for power splitting. A first shaft of the planetary gear
set is coupled to the transmission input, a second shaft of the
planetary gear set is coupled to a first shaft of the variator, and
a third shaft of the planetary gear set is coupled to a second
shaft of the variator. In addition, at least one first shift
element and a second shift element are provided for shifting
between a first gear ratio range and a second gear ratio range,
within which the gear ratio can be continuously varied by the
variator.
According to the invention, the two gear ratio ranges overlap, and
in order to implement the first gear ratio range, the second shaft
of the planetary gear set can be connected to the transmission
output via the first shift element, and to implement the second
gear ratio range, the third shaft of the planetary gear set can be
connected to the transmission output via the second shift
element.
In the transmission device according to the invention, by means of
suitable actuation of the variator between the second shaft and the
third shaft of the planetary gear set, the gear ratio of +1 can be
implemented, so that the variator rotates in the block and a shift
between the first shift element and the second shift element can be
carried out without rotational speed differences. This means that
the shift between the first driving mode and the second driving
mode is synchronous in the transmission device and can be
implemented without impairing the sequence of operation of a work
machine equipped with the transmission device according to the
invention.
Moreover, starting a work machine from a stopped position is
possible with split power, whereby a load on the variator is
reduced in a simple manner in comparison to prior art transmission
devices in which a starting torque is routed entirely via the
variator while starting the work machine.
In addition, the transmission device according to the invention,
which is configured with a single, simple planetary gear set and a
variator, has a simple design and also a small number of
components, so that the transmission device can be assembled with
little expense, is low in cost to manufacture and is distinguished
by a small required installation space.
Another advantageous refinement of the transmission device is
distinguished by a compact design and equipped with a countershaft
arranged parallel to the second shaft of the variator and
operatively connected to the transmission output.
In an additional embodiment of the transmission device according to
the invention distinguished by a small number of components, at
least one idler gear can be connected rigidly to the second shaft
of the variator via the two shift elements and to the third shaft
of the planetary gear set, the idler gear in turn being operatively
connected to a gear wheel of the countershaft.
In another embodiment of the transmission device according to the
invention which is characterized by a simple design and has a
compact design, the two shift elements are arranged on the third
shaft of the planetary gear set or on the second shaft of the
variator.
In order to reduce the load on the variator in a simple and
low-cost manner with regard to the design, and be able to increase
the power which can be transmitted via the transmission device
according to the invention, compared to the power which can be
supplied by transmission devices of conventional design, the second
shaft of the planetary gear set--in one embodiment of the
transmission device--is operatively connected to the first shaft of
the variator via a transmission unit, so that a high gear ratio can
be implemented between the first shaft of the variator and the
second shaft of the planetary gear set.
In an additional embodiment of the transmission device according to
the invention, a reversal of the direction of rotation between the
transmission input and the transmission output can be implemented
by means of a valve device of a hydraulic circuit of the variator
designed as a hydrostatic device, so that the direction of pumping
can be switched in the hydraulic circuit.
In order to implement additional gear ratio ranges, in another
embodiment of the transmission device according to the invention,
between the third shaft of the planetary gear set and the
transmission output, a plurality of gear wheel pairs are provided,
which can be connected via additional shift elements, wherein
according to a refinement of the transmission device, at least one
of the gear wheel pairs is designed with an intermediate gear in
order to implement a reversal of the direction of rotation between
the transmission input and the transmission output.
An additional, advantageous embodiment of the transmission device
according to the invention is equipped with a third shift element,
via which the second shaft of the planetary gear set can be coupled
to the transmission output in order to implement a third gear ratio
range, which overlaps with the second gear ratio range. In this
way, both the change in range between the first and the second gear
ratio ranges, and also the change in range between the second gear
ratio range and the third gear ratio range of the transmission
device according to the invention, are synchronous, that is, they
can be carried out without differences of rotational speed in the
range of the first shift element and of the second shift element
and/or between the second shift element and the third shift
element, using a planetary gear set having only two outputs, which
can be produced cost-effectively and has a simple design.
Therefore, in a very simple manner, depending on the particular
application at hand, the possibility exists to achieve a so-called
modular principle and to design the transmission device according
to the invention solely with the first and the second shift
elements in order to implement a synchronous range change, and to
configure the transmission device additionally with the third shift
element in order to implement two synchronous range changes,
without having to change the fundamental structure of the
transmission device.
This means that the transmission device according to the invention
is configured with or without the third shift element, depending on
whether the transmission device is intended to be used to perform
one or two synchronous range changes, wherein the particular
design, in the case of especially low-cost solutions, can be
achieved without complex design changes to the fundamental
structure of the transmission device.
In order to be able to execute a required change between the gear
ratio ranges in the transmission device according to the invention
as a power shift, the shift elements in another advantageous
embodiment of the transmission device are designed as frictionally
engaging power shift elements.
BRIEF DESCRIPTION OF THE DRAWINGS
Additional advantages and advantageous embodiments of the invention
will be apparent from the claims and in the embodiments described
in principle with reference to the FIGS., wherein for conciseness
in the description of the embodiments, the same reference numbers
are used identical and functionally equivalent components.
Shown are:
FIG. 1 A schematic representation of a vehicle drive train with a
gear diagram of a first embodiment of the transmission device
according to the invention;
FIG. 2 A vehicle drive train with a second embodiment of the
transmission device according to the invention;
FIG. 3 A vehicle drive train with a third embodiment of the
transmission device according to the invention;
FIG. 4 A vehicle drive train with a fourth embodiment of the
transmission device according to the invention; and
FIG. 5 A vehicle drive train with a fifth embodiment of the
transmission device according to the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows a vehicle drive train 1 comprising a drive motor 2, a
transmission device 3 and an output 4 in a highly schematic
representation. The transmission 3 is equipped with a variator 5
designed as a hydrostatic device for the continuous variation of
gear ratios of the transmission device 3. Torque provided by the
drive machine 2 is introduced to the transmission device 3 in the
region of a transmission input 6 and conducted out of the
transmission device 3 in the direction of the drive 4 in the region
of a transmission output 7.
On the transmission input side, the torque applied in the region of
the transmission input 6 is introduced into a planetary gear set 8
via a first shaft 9 designed herein as planet carrier. In the
region of the planetary gear set 8 so-called power splitting of the
torque from the drive motor 2 is performed, wherein a portion of
the torque is divided by a second shaft 10, designed herein as a
ring gear, of the planetary gear set 8 and a third shaft 11,
designed as sun gear, of the planetary gear set 8. The second shaft
10 of the planetary gear set 8 is coupled to a first shaft 12 of
the variator 5 and the third shaft 11 of the planetary gear set 8
is coupled to a second shaft 13 of the variator 5.
For shifting between a first gear ratio range and a second gear
ratio range, the transmission device 3 is designed with two shift
elements 14, 15. Within the two gear ratio ranges, the gear ratio
of the transmission device 3 can be continuously varied by the
variator 5, wherein the ring gear 10 of the planetary gear set 8
can be connected, via the first shift element 14, to a idler gear
16 arranged in a rotatable manner on the second shaft 13 of the
variator 5. The third shaft and/or the sun gear of the planetary
gear set 8 can be connected rigidly to the idler gear 16 via the
second shift element 15. The idler gear 16 meshes with a gearwheel
18 connected rigidly to a countershaft 17, which in turn is
operatively connected to the transmission output 7.
Between the ring gear 10 of the planetary gear set 8 and the first
shaft 12 of the variator 5, a transmission device 19 designed
herein as spur gear toothing is provided, by means of which the
torque conducted from the ring gear 10 of the planetary gear set 8
to the variator 5 is reduced and the rotational speed of the first
shaft 12 of the variator 5 is increased in comparison to the
rotational speed of the ring gear 10.
The two gear ratio ranges which can be engaged in the transmission
device 3 via the shift elements 14 and 15 overlap. In order to
implement the first gear ratio range, the second shaft 10 of the
planetary gear set 8 is connected via the first shift element 14 to
the transmission output 7, and in order to implement the second
gear ratio range, the third shaft 11 of the planetary gear set 8 is
connected via the second shift element 15 to the transmission
output 7, wherein during the change between the gear ratio ranges,
the gear ratio in the region of the variator 5 is set to a value at
which the ring gear 10 and the sun gear 11 of the planetary gear
set 8 rotate at the same rotational speed.
At this synchronous point of the transmission device 3, the shift
element 14 or 15 which is connected is moved from the engaged
operating state thereof into the disengaged operating state
thereof, while the respectively disconnected shift element 15 or 14
is moved from the disengaged operating state thereof into the
engaged operating state thereof, wherein during the switch between
the two shift elements 14 and 15 no rotational speed difference
must be overcome.
The variator 5 and/or the hydrostatic unit is equipped with a pump
and a motor in a bent-axis design, which are force-coupled via a
common pivot unit, and thus has a simple and cost-effective control
using only one adjusting mechanism. Depending on an actuation angle
of the common pivot part between the motor and the pump of the
variator 5, which can pivot between 0.degree. to about 45.degree.,
the rotational speeds of the first shaft 12 and of the second shaft
13 of the variator 5 alternate in the end positions of the pivot
part between shaft stoppage and maximum rotational speed.
Depending on the particular application at hand, however, it is
also possible to design the variator with units which can be set
independently of each other.
In principle, the directions of rotation of the shafts 12 and 13 of
the variator 5 are such that while the vehicle equipped with the
vehicle drive train 1 drives forward and the pivot part of the
variator 5 pivots in the region of the two shift elements 14 and
15, the synchronous operation necessary for the synchronous change
in gear ratio can be set, wherein the directions of rotation of the
two shafts 12 and 13 of the variator 5 are in principle opposite of
each other.
The transmission device 3 is equipped with a single, simple
planetary gear and a variator 5, which is arranged in the manner
described above between two shafts 10 and 11 of the planetary gear
set 8, in order to be able to implement the largest possible,
continuous driving mode during a synchronous switch between the two
shift elements 14 and 15. Moreover, starting from a vehicle
standstill can be carried out in a power-split manner when using
the transmission device 3.
With the vehicle stopped, the pivot part of the variator 5 is
pivoted such that the first shaft 12 of the variator 5 is locked by
variator-internal states, and the second shaft 13 of the variator 5
can freely rotate without power transmission, wherein the
countershaft 17 and also the transmission output 7 are locked when
the first shift element 14 is engaged and are fixed like the output
4.
If the pivot part of the variator 5 is pivoted out of the
above-mentioned position, the first shaft of the variator 12 begins
to rotate and the second shaft 13 of the variator 5 begins to take
up power. In the region of the first shift element 14, the torque
applied via the ring gear 10 of the planetary gear set 8, which is
now supported in the region of the variator 5, is transferred, via
the idler gear 16 and the gearwheel 18, to the countershaft 17 and
thus to the transmission output 7, whereby the output 4 and/or the
vehicle equipped with the vehicle drive train 1 begins to roll. The
first shift element 14 remains engaged in the entire first gear
ratio range and/or driving mode of the transmission device 3.
Proceeding from the operating state of the transmission device 3
last-described above, an increasing adjustment angle of the pivot
part of the variator 5 during the vehicle's starting process causes
a gear ratio having a value of +1 to be set in the region of the
planetary gear set 8 between the sun gear 11 and the ring gear 10
at a predefined operating point of the variator 5. The ring gear 10
and the sun gear 11 then have the same rotational speed and the
planetary gear set 8 revolves in the block. In this operating state
of the transmission device 3, a switch can be carried out between
the two shift elements 14 and 15 without rotational speed
difference.
In order for the adjusting range of the variator 5 in the first
gear ratio range and in the second gear ratio range to be used
repeatedly and for the power transmittable via the transmission
device 3 to be increased using a simple design, the transmission
device 10 is arranged between the first shaft 10 of the planetary
gear set 8 and/or the ring gear and the first shaft 12 of the
variator. By means of the transmission device 10, a high gear ratio
can be implemented between the first shaft 12 of the variator 5 and
the ring gear 10 of the planetary gear set 8, whereby due to the
arrangement of the transmission device 19, the synchronous point in
the region of the two shift elements 14 and 15 is reached not until
an adjusting angle of the pivot part is clearly greater than half
the total pivot angle.
After switching from the first shift element 14 in the direction of
the second shift element 15, the pivot angle of the variator 5 is
reduced in order to increase the rotational speed of the output
drive shaft and/or the rotational speed of the countershaft 17. The
greatest rotational speed of the countershaft 17 and/or of the
transmission output 7 is reached when--with the second shift
element 15 engaged--ring gear 10 of the planetary gear set 8 is
blocked by the variator 5. In this operating state of the
transmission device 3, the sun gear 11 of the planetary gear set 8
is driven without power transmission in the region of the variator
5, since the entire torque of the drive motor 2 is conducted, via
the second shift element 15, to the output 4.
In order also to be able to provide a gear ratio range for reverse
driving with the transmission device 3 without additional
mechanical components, the transmission device 3 can be designed
with a device (not illustrated in detail) which can switch the
hydraulic pumping direction in the region of the variator 5 when
the vehicle is stopped. It is conceivable that the hydraulic
circuit of the variator 5 can be equipped with a valve device known
from DE 10 2006 025 348 A1.
FIG. 2 shows a second embodiment of the transmission device 3 which
differs from the embodiment illustrated in FIG. 1 in the region
between the sun gear 11 of the planetary gear set 8 and the
transmission output 7 due to additional gear sets 20 to 20n as well
as shift elements 21 to 21n associated therewith, in order to make
available additional gear ratio ranges which can be engaged by
power shift processes in the transmission device 3. The letter n
added after the particular reference numbers 20 and 21 in each case
denote the particular integral quantity of additional gearwheel
pairs and shift elements of the transmission device 3, which varies
as a function of the particular application at hand. The
transmission device 3 must be designed with additional gear ratio
ranges if a vehicle designed with the vehicle drive train 1 is to
be operated at higher final speeds.
In principle, a change in gear ratio in the transmission device 3
between the first shift element 14 or the second shift element 15
and the third shift element 21 and/or the additional shift elements
21n can only be carried out in a non-synchronous operating state of
the transmission device 3. Nonetheless, during changes between the
first gear ratio range or the second gear ratio range and the third
or the n-th gear ratio range, the possibility exists to reduce the
rotational speed difference to be bridged during the shift process
by adapting the gear ratio of the variator 5.
In the third embodiment of the transmission device 3 illustrated in
FIG. 3, the ring gear 10 of the planetary gear set 8, in addition
to the first shift element 14 and the idler gear 16 and the gear
wheel 18, can be operatively connected to the countershaft 17 via
an additional shift element 22. To this end, an idler gear 23
rotatably arranged on the sun gear 11 of the planetary gear set 8
can be connected rigidly to the ring gear 10 of the planetary gear
set 9 via the additional shift element 22. The idler gear 23 meshes
with an intermediate gear 24 which, in turn, engages with a fixed
gear 25 of the countershaft 17.
Therefore, a gear set including the intermediate gear 24 can be
connected via the additional shift element 22 between the ring gear
10 of the planetary gear set 8 and the transmission output 7 in
power flow of the transmission device 3. The shift between the
first shift element 14, the second shift element 15 or the
additional shift element 21 and the additional shift element 22 in
each case is carried out at low rotational speeds of the output 4
or with the output 4 stopped. The shifts each represent reverse
shifts by which reverse driving of a vehicle equipped with the
vehicle drive train 1 according to FIG. 3 is possible.
In contrast to the embodiments of the transmission device 3 as per
FIG. 1 and FIG. 2, an idler gear 26 can be connected rigidly, via
the second shift element 15, to the sun gear 11 of the planetary
gear set 8, the idler gear meshing with an additional fixed gear 27
of the countershaft and not forming an integral unit with the idler
gear 16. The change in the gear ratio range during which a switch
occurs between the first shift element 14 and the second shift
element 15, can be implemented synchronously through a
corresponding actuation of the variator 5, that is, without
rotational speed difference in the region of the shift elements 14
and 15.
FIG. 4 and FIG. 5 show a fourth and fifth embodiment, respectively,
of the transmission device 3, which have basically the same design
and which differ from the embodiments of the transmission device 3
illustrated in FIG. 1 to FIG. 3 in that two synchronous range
changes can be carried out with the transmission devices 3 as per
FIG. 4 and FIG. 5.
The transmission devices 3 according to FIG. 4 and FIG. 5 are
therefore designed with the two shift elements 14 and 15 and also
with a third shift element 28. In order to implement the first gear
ratio range of the transmission device 3, the second shaft and/or
the ring gear 10 of the planetary gear set 8 are connected in the
engaged state of the first shift element 14 to the transmission
output 7, wherein an idler gear 29, which is rotatably arranged on
the countershaft 17 and which meshes with a fixed gear 30 rigidly
operatively connected to the ring gear 10, is rigidly connected to
the countershaft 17 in the engaged state of the first shift element
14.
Proceeding from an operating state of the vehicle drive train 1,
for which the first gear ratio range is engaged in the transmission
device 3 via the engaged first shift element 14, and with the
vehicle being stopped, the variator 5 is adjusted to the first
extreme position thereof, in which the rotational speed of the
first shaft 12 of the variator 5, which is connected to a motor
device of the variator 5, is equal to zero. The ring gear 10
connected to the first shaft 12 of the variator 5 via the
transmission device 19 is likewise stopped in this operating state.
If an appropriate command is present for a starting process of the
vehicle designed with the vehicle drive train 1, then the variator
5 is pivoted out of the aforementioned, first extreme position via
a preferably common yoke and the rotational speed and/or the motor
rotational speed of the variator's motor increases. This at the
same time means that the rotational speed of the output 4 of the
vehicle designed with the transmission device 3 increases and the
vehicle starts to move.
In order to continuously increase the vehicle's speed, the variator
5 is adjusted from the first extreme position thereof into the
second extreme position thereof, and the first gear ratio range of
the transmission device 3 is driven continuously. In the process,
the rotational speed of the motor of the variator 5 rises
increasingly in the direction of the maximum value thereof, while
the rotational speed of the variator's pump decreases from the
maximum value thereof to zero. In the second extreme position of
the variator 5, in the region of the second shift element 15, the
synchronous point materializes, whereby the second shift element 15
can be transferred into the engaged operating state thereof without
rotational speed difference, while the first shift element 14 is
disengaged.
After a successful synchronous range change from the first gear
ratio range into the second gear ratio range and in the presence of
an additional command to increase the vehicle speed, the variator
5, starting from the second extreme position thereof, is again
pivoted in the direction of the first extreme position thereof.
This causes the rotational speed of the second shaft of the
variator 13 to increase, while the rotational speed of the ring
gear 10 is reduced.
At a predefined pivot angle of the yoke of the variator 5, which
depends on the gear ratio of the spur gear toothing formed by the
idler gear 29 and the fixed gear 30, the synchronous point is
reached simultaneously in the region of the second shift element 15
and in the region of the third shift element 28, whereby a second
synchronous range change can be carried out between the second gear
ratio range and the third gear ratio range in the transmission
device 3 without rotational speed difference between the second
shift element 15 and the third shift element 28.
In the fourth embodiment of the transmission device 3 illustrated
in FIG. 4, the third shift element 28 is arranged on the
countershaft 7 and rigidly couples an idler gear 31, which is
arranged on the countershaft 7 and meshes with a fixed gear 32
rigidly connected to the ring gear 10, to the countershaft 7 in the
engaged state of the shift element.
In the fifth embodiment of the transmission device 3 illustrated in
FIG. 5, the third shift element 28 is arranged on the second shaft
13 of the variator 5 and connects an idler gear 33 rotatably
arranged on the second shaft 13 of the variator 5 to the ring gear
10 of the planetary gear set 8 in the engaged state of the shift
element. The idler gear 33 meshes with a fixed gear 34 rigidly
connected to the countershaft 17, whereby an operative connection
is created between the ring gear 10 and the transmission output 7
in the engaged state of the third shift element 28.
Both with the transmission device 3 according to FIG. 4, and also
with the transmission device 3 according to FIG. 5, two synchrouns
range changes can be implemented using a planetary gear set having
only two output shafts which is cost-effective to produce and has a
simple design.
In principle, the fourth and the fifth embodiments of the
transmission device 3 each represent an expanded system in
comparison to the embodiments of the transmission device 3
illustrated in FIG. 1 to FIG. 3, wherein depending on the
particular application at hand one or two synchronous range changes
can be carried out if the transmission device 3 has the necessary
design for this.
In this connection, in order to achieve a modular principle the
transmission device 3 ideally must be designed such that, depending
on the demand for a two- or three-speed transmission having one or
two synchronous range changes, the third shift element 28 is
provided or the transmission device 3 is designed without the third
shift element 28.
The shift elements 14, 15, 21 to 21n, 22 and 28 of the embodiments
of the transmission device 3 illustrated in the drawing are all
designed as frictionally engaged multi-disk clutches and/or
frictionally engaged shift elements, in order to be able to
implement the change between the gear ratios ranges to be carried
out in the transmission device 3 without interruption in the torque
flow.
In contrast to the embodiments illustrated in the drawing and
explained in greater detail in the description above, the
transmission device according to the invention can also be designed
with different variators by which the transmission of power from
the drive machine 2 in the direction of the output 4 can be
continuously transmitted and varied. This means that the
transmission device 3 according to the invention can also be
designed with other suitable embodiments of a variator, such as a
variable speed gear, a friction wheel-type variator, two mutually
operatively connected electric motors and the like, wherein in the
realm of agricultural machines, the design of a variator as
hydrostatic device is preferred, since this variant has the greater
power density.
LIST OF REFERENCE NUMERALS
1 Vehicle drive train 2 Drive motor 3 Transmission device 4 Output
5 Variator 6 Transmission input 7 Transmission output 8 Planetary
gear set 9 First shaft of planetary gear set 10 Second shaft of
planetary gear set 11 Third shaft of planetary gear set 12 First
shaft of variator 13 Second shaft of variator 14 First shift
element 15 Second shift element 16 Idler gear 17 Countershaft 18
Gear wheel 19 Transmission unit 20 to 20n Gear wheel pairs 21 to
21n Shift elements 22 Additional shift element 23 Idler gear 24
Intermediate gear 25 Gear wheel 26 Idler gear 27 Fixed gear 28
Third shift element 29 Idler gear 30 Fixed gear 31 Idler gear 32
Fixed gear 33 Idler gear
* * * * *